1. Field of the invention
This invention relates to security bars of the type mountable over a window to keep out intruders. More particularly, it relates to security bars that are easily removable by a person inside the protected structure.
2. Description of the prior art
Early security bars were mounted to the exterior of occupied structures, in registration with windows, to prevent unauthorized access into the protected structure. Although such devices performed their intended function, they also prevented escape through such windows when fire or other emergency conditions mandated such escape.
Accordingly, inventors turned their attention to security bars that could be mounted on the interior side of the windows so that such bars could be removed to allow egress from the structure if required. Examples of interior-mounted security bars may be seen in U.S. Pat. Nos. 5,018,302 to Kluge, 4,243,090 to Kemp, Re 17,978 to McWane, and 785,690 to Wolfe. Although such constructions represent considerable improvements over the exterior mounted, somewhat dangerous security bars of the past, they lack a number of important features.
For example, the art fails to teach security bar assemblies having width adjustment means so that such assemblies could be used with windows of varying widths. Consequently, the art fails to suggest how interior mounted security bars could be provided with width adjustment means.
Moreover, the art fails to teach interior-mounted security bar assemblies that are very quickly and easily removable. Some earlier devices appear at first glance to be quickly and easily removable, but are found to be otherwise upon close inspection. More particularly, some designs are mechanically complex and thus tend to jam when an effort is made to remove them quickly. Once jammed, they are difficult to un-jam.
What is needed, then, is an interior-mounted security bar assembly that fits windows of differing widths and which has an elegant design so that it can be removed quickly and easily without jamming. However, when the art of interior and exterior-mounted security bar assemblies was considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill how the needed assembly could be created.